Aluminum 249.0-T4 vs 249.0-T6
Aluminum · 249.0 temper comparison
249.0-T4 and 249.0-T6 are two conditions of the same aluminum grade, 249.0: T4 (solution heat treated and naturally aged) versus T6 (solution heat treated and artificially aged). The chemistry is identical, so every difference below comes from the condition. 249.0-T6 is the stronger of the two: yield strength 380 MPa (55.1 ksi) against 200 MPa (29 ksi) for 249.0-T4, about 90% more; tensile strength follows at 440 MPa (63.8 ksi) vs 330 MPa (47.9 ksi). In exchange, 249.0-T4 is the more ductile: elongation 12% versus 4% for 249.0-T6, and 249.0-T6 is harder (125 HB vs 85 HB). 249.0-T6 runs hotter in service (150°C vs 100°C continuous). On the shop floor, 249.0-T6 machines more easily (very good vs good).
249.0-T4Choose it when the part is bent, formed or impact-loaded.
249.0-T6Choose it when strength drives the design, or when the part sees heat.
249.0-T4 vs 249.0-T6: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 71 GPa10.3 Msi · Shear Modulus 26.5 GPa3.8 Msi · Bulk Modulus 70 GPa10.2 Msi · Poisson's Ratio 0.33 · Compressive Strength 350 MPa50.8 ksi
Physical
Density and transition temperatures.
Same in both: Density 2.81 g/cm³0.1 lb/in³ · Melting Point (Solidus) 540°C1,004 °F · Liquidus Temperature 640°C1,184 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 900 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 22.8 µm/m·K12.7 µin/in·°F · Latent Heat of Fusion 390 J/g168 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Same in both: Electrical Resistivity 5.2×10⁻⁸ Ω·m2.05 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.7 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Same in both: Machinability Rating (AISI 1212 = 100 %) 60% · Weldability 25 / 100 · Castability 40 / 100 · Brazeability / Solderability 15 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Carbon (primary production) 12.5 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 10%
Strength versus weight
Yield strength against density for every aluminum grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
249.0-T4 vs 249.0-T6 — frequently asked
Is 249.0-T6 stronger than 249.0-T4?
Yes. 249.0-T6 has a typical yield strength of 380 MPa (55.1 ksi) against 200 MPa (29 ksi) for 249.0-T4 — about 90% more. Tensile strength is 440 MPa (63.8 ksi) vs 330 MPa (47.9 ksi).
Which condition does FabDigit quote by default, T4 or T6?
T7 is the default 249.0 condition in the FabDigit quote flow (neither T4 nor T6). The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, 249.0-T4 or 249.0-T6?
249.0-T6. Its machinability rates very good (78/100) against good (65/100) for 249.0-T4.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 249.0-T4 and 249.0-T6 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.